Method of producing ferromanganese powder



United States Patent 3,346,363 METHOD OF PRODUCING FERROMANGANESE POWDER Gerhard Naeser, Duisburg-Huckingen, and Werner Schulz, Duisburg-Ungelsheim, Germany, assignors to Mannesmann Aktiengesellschaft, a corporation of Germany No Drawing. Filed Feb. 23, 1966, Ser. No. 529,250 Claims priority, application Germany, Feb. 22, 1965, M 64,252 4 Claims. (Cl. 75.5)

The invention relates to the production of ferromanganese powder, and relates more particularly to the method of such production wherein molten ferromanganese is atomized with the aid of either steam or pressurized water, and the liquid droplets thereafter are chilled in a water bath.

Large quantities of ferromanganese powder are needed as an additive for the coating of welding electrodes. In accordance with a conventional method, the powder is produced by first breaking cast blocks of ferromanganese and thereafter grinding to a fine powder the broken block parts in heavy pebble mills. This method of the prior art, however, has met with difficulties. Ferromanganese is brittle, so that during the grinding there occurs a large part of dust-like powder; this dust-like powder, however, is not usable as an additive in the coating of electrodes, and therefore needs to be recast. Furthermore, the grinding must be carried out under a protective gas cover, which requires the observing of explosive protective measures to avoid the occurrence of dust explosions.

In order to avoid the aforesaid drawbacks, it has been proposed to produce ferromanganese powder by atomizing molten ferromanganese with the aid of either steam or pressurized water. In accordance with that method, the molten ferromanganese that emerges from an annular nozzle is atomized either with the aid of steam or pressurized water into fine droplets, which are subsequently chilled in a water bath. The powder obtained in accordance with that method, however, is not usable for the coating of welding electrodes. It has been found that electrodes coated with a mass containing ferromanganese powder produced in accordance with this method spray strongly, and cause the formation of detrimental pores in the welding seams.

It is among the principal objects of the invention to produce ferromanganese powder free from the drawbacks of the prior art.

It is another object of the invention to provide a method for the production of ferromanganese powder so that the powder will not cause any of the difiiculties of the powders of the prior art.

It is a further object of the invention to provide a method for producing ferromanganese powder that requires no special or expensive safety measures, and will produce powder usable in the coating of welding electrodes.

It is still another object of the invention to provide a method for producing ferromanganese powder by atomizing molten ferromanganese with the aid of either steam or pressurized water, and chilling the resulting fine droplets, and subsequently heating the chilled powder in a hydrogen-free atmosphere.

Further objects and advantages of the invention will be ICC set forth in part in the following specification and in part will be obvious therefrom without being specifically referred to, the same being realized and attained as pointed out in the claims hereof.

The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others, all as exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

In accordance with the instant invention, molten ferromanganese emerges from an annular nozzle in the form of a jet, is atomized with the aid of either steam or pressurized water into fine droplets, and these fine droplets are subsequently chilled in a water bath. Thereafter, the chilled powder either with or without an intervening predrying step, is heated to a temperature of from about 200 C. to 400 C., preferably a temperature of about 280 C., in a hydrogen-free atmosphere, for instance in dry air.

Example After the atomizing of molten ferromanganese of conventional composition, with the aid of pressurized water, the resulting powder had a hydrogen content of 37 cubic centimeters per grams. The following percentages thereof were removed during the subsequent heat treat- Where still higher heating temperatures are applied, they change the hydrogen content only little; furthermore, there exists then the danger of oxidation of the powder.

The powder that had been heated above 200" C. caused no difliculties during electric welding, while the powder which either had not been heated at all or only to a temperature below 200 C., led to blistery welding seams and to a strong spraying during welding.

We wish it to be understood that we do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

Having thus described the invention, what we claim as new and desire to be secured by Letters Patent, is as follows:

1. In a method of producing ferromanganese powder, wherein molten ferromanganese is atomized with the aid of steam or pressurized water and the liquid droplets are chilled in a water bath, the steps comprising heating the chilled powder at a temperature of from about 200 C. to about 400 C. in a hydrogen-free atmosphere.

2. In a method, as claimed in claim 1, the step of predrying the chilled powder prior to the heating.

3. In a method, as claimed in claim 1, the heating temperature being about 280 C.

4. In a method, as claimed in claim 1, said hydrogenf ree atmosphere being dry air.

No references cited.

DAVID L. RECK, Primary Examiner. W. W. STALLARD, Assistant Examiner. 

1. IN A METHOD OF PRODUCING FERROMANGANESE POWDER, WHEREIN MOLTEN FERROMANGANESE IS ATOMIZED WITH THE AID OF STEAM OR PRESSURIZED WATER AND THE LIQUID DROPLETS ARE CHILLED IN A WATER BATH, THE STEPS COMPRISING HEATING THE CHILLED POWDER AT A TEMPERATURE OF FROM 200*C. TO ABOUT 400*C. IN A HYDROGEN-FREE ATMOSPHERE. 